I have a Leonard Messel that I've had in a bonsai training pot for quite a few years now. I haven't been able to reduce the leaf size much nor get a lot of ramification (increasing that might lead to reduced leaf size). I think these have to be developed with the winter/early spring silhouette in mind (they look really interesting when the buds swell and start to open). Once in leaf though, I think they are sort of like wisteria in that you put them toward the back of the bench. Maybe if you make a pretty large bonsai out of one it could look ok in leaf.
